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Catheter–based percutaneous renal denervation (RDN) has shown durable reduction of blood pressure in patients with uncontrolled hypertension. Since RDN is a bilateral procedure, studying a possible cross–talk mechanism between contralateral treated kidneys over time can help explain time dependent clinical efficacy, as demonstrated in human subjects.
We used the V2 System™ (Vessix Vascular Inc., Laguna Hills, CA) for the renal denervation procedures. The V2 System consists of a proprietary bipolar RF generator and an over–the–wire low pressure balloon catheter with an array of radiofrequency (RF) electrodes mounted on the exterior in an offset helical pattern. Each temperature controlled dose (68°C) of bipolar energy is delivered for 30 seconds. A total of 24 healthy juvenile Yorkshire swine were treated bilaterally. Efficacy was evaluated at 14, 28 and 90 days post treatment using an HPLC–MS/MS method to measure kidney tissue norepinephrine (NEPI). In addition, histopathologic methods were used to assess the percentage of affected nerves in the renal arteries.
A positive, time dependent correlation between the percentage of affected nerves per artery and reduction in kidney NEPI concentration levels was found, reaching the strongest correlation at 90 days post procedure (r=0.8). The average differential of affected nerves in contralateral renal arteries (right vs. left) showed a non–significant reduction with time. However, while the number of affected nerves was virtually unchanged, a significant reduction in the average NEPI differential between contralateral kidneys is shown at 90 days vs. 28 (and 14) days post procedure (p=0.01).
Although the differential between percentage of affected nerves of contralateral renal arteries does not change significantly during the 90 days post procedure, NEPI concentration in the kidneys demonstrate shifting until they become comparable to each other, indicating potential cross–talk between kidneys following renal denervation.
Poster Sessions, Expo North
Sunday, March 10, 2013, 3:45 p.m.–4:30 p.m.
Session Title: Vascular Medicine: Endovascular Therapy III
Abstract Category: 34. Vascular Medicine: Endovascular Therapy
Presentation Number: 1253–163
- 2013 American College of Cardiology Foundation